1. Field of the Invention
The present invention is generally related to an acceleration control system and, more particularly, to a system which allows the operator of a marine vessel to select an acceleration profile according to which the propulsion system of the marine vessel will be controlled, particularly during initial acceleration from a stationary condition to a final velocity.
2. Description of the Related Art
Many different devices and methods are known to those skilled in the art for controlling the speed of a marine vessel.
U.S. Pat. No. 5,074,810, which issued to Hobbs et al. on Dec. 24, 1991, describes an automatic speed control system for boats. The speed of the boat is measured and compared to a desired speed set by the operator and the speed of the boat engine is adjusted to minimize the difference between the desired speed and the actual speed. The device further incorporates features allowing incremental adjustment of the desired speed, storage of several of these speeds for future use, and a safety feature causing the system to behave as though it were a conventional manual type if the operator makes a gross change to the setting of a manual throttle lever.
U.S. Pat. No. 5,110,310, which issued to Hobbs on May 5, 1992, describes an automatic speed control system for boats. Actual speed is compared to a desired speed set by the operator and the speed of the boat engine is adjusted to minimize the difference between the desired speed and the actual speed. Engine speed is further adjusted to prevent or minimize changes in the speed of the boat caused by the forces on the boat due to a water skier. The device further incorporates features to reduce the likelihood of speed measurement errors due to a malfunctioning speed measuring device.
U.S. Pat. No. 5,700,171, which issued to Horton on Dec. 23, 1997, describes a speed control system. It comprises speed sensors which output to a controller which, in turn, outputs to a servo motor. The servo is connected to the inner cable of a coaxial cable, the outer sheath of which is lodged between a buttress and the engine throttle. The distance between the buttress and the engine throttle lever is, at least when the throttle is closed, shorter than the length of the outer sheath such that the outer sheath obtains a curved configuration. The inner cable extends beyond the engine throttle lever to a support. Accordingly, when the controller operates the servo to draw in the inner cable, the outer sheath is urged to straighten and, thereby, push against the engine throttle lever to open it. Conversely, when the inner cable is paid out, the outer sheath is relaxed to allow the engine throttle lever to close.
U.S. Pat. No. 6,109,986, which issued to Gaynor et al. on Aug. 29, 2000, discloses an idle speed control system for a marine propulsion system. The system controls the amount of fuel injected into the combustion chamber of an engine cylinder as a function of the error between a selected target speed and an actual speed. The speed can be engine speed measured in revolutions per minute or, alternatively, it can be boat speed measured in nautical miles per hour or kilometers per hour. By comparing target speed to actual speed, the control system selects an appropriate pulse width length for the injection of fuel into the combustion chamber and regulates the speed by increasing or decreasing the pulse width.
U.S. Pat. No. 6,485,341, which issued to Lanyi et al. on Nov. 26, 2002, discloses a method for controlling the average speed of a vehicle. The speed of the vehicle is controlled over a predetermined time period, or indefinitely, or distance length. The system comprises the steps of selecting a desired average speed, measuring an actual speed, and maintaining a cumulative error determined as a function of the difference between the average speed and the actual speed and the time over which the actual speed measurement was taken. Based on the cumulative total or speed time error, a compensatory speed is calculated that will reduce the cumulative speed time error to an acceptable tolerance range within a selected period of elapsed time. Although particularly applicable to competition situations in which an average speed is dictated for use over a particular competition course, the average speed controlling method can be used in other situations where the average speed of a vehicle must be controlled.
U.S. Pat. No. 6,738,708, which issued to Suzuki et al. on May 18, 2004, describes an engine speed controller for a marine propulsion engine. An electronically controlled engine speed system for an outboard motor regulates the speed of the engine to insure proper watercraft speed. A remote input device can program the preferred embodiments of the system. The preferred embodiments of the system recognize an engaged transmission and control engine speed by changing the ignition timing, fuel injection amount, and throttle bypass valve.
U.S. Pat. No. 6,855,020, which issued to Kaji on Feb. 15, 2005, describes a running control device for a watercraft. The device for a watercraft with a propulsion device capable of controlling propulsion, comprises a propulsion control section which controls propulsion, based on predetermined input information, the propulsion control section comprises a target propulsion calculation module for determining a target propulsion, based on predetermined input information including at least velocity of the watercraft and an operation amount calculation module for determining the amount of operation of the propulsion device, based on predetermined input information so as to obtain the target propulsion determined by the propulsion calculation module.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
In certain applications of marine vessels, such as towing a water skier or wake boarder, the rate of acceleration from a standstill position to a final velocity condition is often as important or more important than maintaining a steady velocity for the water skier. If the acceleration is too rapid, novice or intermediate water skiers may not be able to satisfactorily move from a resting position to a water skiing position wherein the skier is being towed at a final velocity behind the marine vessel. An expert water skier, on the other hand, may wish to accelerate more rapidly from a resting position in the water to a position and condition in which the water skier is being pulled at a final velocity behind the marine vessel.
It would therefore be significantly beneficial if the acceleration of the watercraft can be controlled precisely to perform according to a preselected acceleration curve and repeat that curve during subsequent accelerations of the marine vessel from a resting condition to a final velocity condition.